1. Field of the Invention
The present invention relates to a pressure sensor using piezoresistance of semiconductor silicon.
2. Description of the Prior Art
A pressure sensor using piezoresistance of semiconductor silicon has a gauge resistance at a thin portion (diaphragm) and detects pressure by measuring the piezoresistance thereof. The pressure sensor is used within a pressure range where a pressure against resistance characteristic is linear.
It is known that if a pressure exceeds a limit, nonlinearities due to the balloon effect of the silicon diaphragm become large and the linearity of the pressure sensor worsens. The size of the sensor's diaphragm determines an upper limit of pressure (rated pressure) beyond which the response of the sensor becomes nonlinear. Previously, the size of the diaphragm satisfying linearity of pressure up to a prescribed pressure could be determined only by producing trial products, and it is difficult to determine the size of the diaphragm.